定语从句
定语从句在句中做定语，修饰一个名词或代词，有时也可以修饰部分或整个句子。

被修饰的名词，词组或代词即先行词。

定语从句通常出现在先行词之后，由关系词（关系代词或关系副词）引出。

关系代词有：who, whom, whose, that, which, as。

关系副词有：when, where, why, how。

关系代词和关系副词放在先行词和定语从句之间，起连接作用，同时又可做定语从句的一个成分。

当关系代词做宾语时可以省略。

定语从句中的谓语动词必须在人称上和数量上和先行词保持一致。

定语从句分为限制性定语从句和非限制性定语从句。

关系代词和关系副词的作用：
一、关系代词
1. 先行词指物时，关系代
词用that 或which（在句中作主语或宾语）。

如：China is a country which / t hat has a large population. The computer game which/ that he is playing is his favo rite.
2.先行词指人时，关系代词用（who）作主语或宾语，whom (作宾语)，whose (作定语)，that (作主语或宾语)。

如： The man who is mending the machine has been retired.
This is the policeman who/ whom they were talking about yesterday.
I like the girl whose mother is an actor.
注意：下列情况下关系代词只用that 而不用which 或 who。

1. 先行词是指物的不定代词，如：all, little, few, much, none, a nything, nothing, everything 等时。

如：I didn't understand the
words all that he said.
2．先行词由最高级、序数词以及any, very, only, all, no, just 等所修饰。

如：This is the most beautiful place that I have been to .
3.先行词既包括人，也包括物。

如：They always like to talk about the man and the things that they see on the road. . 4当主句是以which 或who 开头的特殊疑问句时。

如：who is the man that opened up the lab？.
二、关系副词引导的定语从句
关系副词可代替先行词是时间、地点、方式或理由的名词，在从句中作状语。

关系副词when, where, why, how的含义相当于"介词+ which"结构，因此常常和"介词+ which"结构交替使用，例如：
I still remember the day when I was invited by the teacher last year.
It is the place that he visited last year.
Beijing is the place where (in which) I was born.
Is this the reason why (for which) he refused our offer? I'm surprised the way how (by which) he works out the problem.
三、例题解析：举一反三，学的更轻松！
1. He is a friend ______ ca n help you in time of need.
A. who he
B. whose
C. /
D. who
解析：引导词在定语从句中做主语，指人。

应选D 。

2.The most important thing ______ we should pay attention to is the first thing ______ I have said.
A. which, that
B. that, which
C. which, which
D. that, that
解析：先行词前有序数词，最高级时，引导次只能用 that. 应选D.
3. This is the only one of these books that ______ worth reading.
A．has B. have C. is D. are 解析：引导词that在句中作主语，代指one ，应选C。

4.The man ______ talked t o you just now is my father.
A. who
B. he
C. whi ch
D. whose
解析：引导词在句中作主语指人，应选A.
5.They thought too much about ______.
A. which I had said
B. what I had said
C. that I had said
D. I had said
解析：此题引导词作在从句中作宾语，表示说话的内容，应选B。

练习与巩固：熟能生巧，
取得好成绩！
一、选择最佳答案填空：1．Did you find the notebook ______ Jim had given me for my birthday?
A. who
B. whom
C. which
D. whose
2. That's all ______ I have seen and heard.
A. which
B. that
C. where
D. what
3. Have you seen the man _ _____ plan we were talking about ______ yesterday ?
A. who, them
B. its, them
C. whose,/
D. whose, them
4.The Oscar is one of the film prizes ______ offered to any Chinese actor or actress so far.
A. which are not
B. that have not been
C. that has not
D. that has not been
5. He never reads anything ______ is not worth reading.
A. that
B. as
C. who
D. which
6. The man ________ coat is black is waiting at the gate.
A. who's
B. whose
C. that
D. of which
7. _________ cleans the classroom can go home first.
A. Anyone
B. those who
C. However
D. The one who
8. The police caught the
man _______ stole my hand bag.
A. he
B. that
C. whom
D. which
9. The girl ________ is reading under the tree _____ ___ my sister.
A.which, is
B. whom, was
C.who , is
D. who, was
10. George Mallory was an English teacher _______ loved climbing.
A. who
B. whom
C. he
D. which 1-5 CDCBA
6-10 BDBCA。